1. Field of the Invention
The present invention relates to an improvement in a seat belt device which is adapted to detect an abrupt deceleration of a vehicle body, which may be caused at the time of collision, etc., thereby to lock an emergency locking type retractor (ELR).
2. Description of the Prior Art
Such a device has been generally known that is provided with an emergency locking type retractor, and in which when an excessively great deceleration is caused to the vehicle body due to collision of the vehicle or the like, said deceleration is detected and the retractor is placed in a locked state to stop drawing-out of a webbing, thus restricting occupants to a safe posture. See "Jidosha Kogaku Zensho No. 16 (Automotive Engineering Compendium 16) --Safety of Automobile" issued by Sankaido.
An emergency locking type retractor is designed to detect an abrupt deceleration of the vehicle body and stop rotation of a shaft with webbing wound therearound. The webbing which is wound around the shaft several times over becomes tightened owing to an excessively great tension applied to the webbing when the vehicle collides. This normally causes an elongation the webbing of approximately 100 mm (the length of the webbing which is drawn out from the retractor before the tractor locks).
In view of the foregoing, to prevent such an elongation, a locking mechanism has been provided at an outlet for the retractor so as to minimize the drawn-out or elongation of the webbing by clamping the webbing in a fixed state. This arrangement poses a problem in that there is still caused an elongation of approximately, 30 mm.